This invention relates to a transmit/receive switching system and more particularly to a switching system particularly adapted to be utilized in a sonar system.
The prior art transmit/receive switching circuits utilize an electromechanical relay to disconnect the receiver from the transducer during the time that the transmitter is providing power to the transducer. The use of electromechanical relays with their attendant power supply requirements not only occupies valuable space in the environment in which sonar is customarily employed, but also the wiring to the energizing coil of the relay tends to induce hum occurrence into the input of the amplifier which is connected to the relay contacts. Because the signals received by the transducer are of the same order of magnitude as the signals induced by the power supply to the coil of the relay, substantial difficulties are produced especially where the relay is located at some distance from the preamplifier.
It is therefore an object of the present invention to provide the required isolation between the receiver and the transmitter without utilizing electromechanical components by the use of only solid state components which are in general more reliable and less expensive and which do not have the power supply requirements nor the space requirements of the electromechanical relays.